Venule

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A venule is a small blood vessel that allows blood to return from the capillary beds to the larger blood vessels called veins. Venules have three layers: An inner endothelium composed of squamous epithelial cells that act as a membrane, a middle layer of muscle and elastic tissue, and an outer layer of fibrous connective tissue. The middle layer is poorly developed so that venules have thinner walls than arterioles.